EMP protection for structures having coal combustion residual components

ABSTRACT

An electromagnetic emission shield for protecting a facility having a volume of coal combustion residue. The shield includes a carbon-based material positioned inside an interior space of the coal combustion residue proximate to and interposed between a potential source of electromagnetic emission and the facility.

CROSS REFERENCE TO RELATED PATENT APPLICATIONS

This utility patent application claims priority from U.S. ProvisionalApplication No. 62/863,394, filed Jun. 19, 2019 and U.S. patentapplication Ser. No. 16/711,581, filed Dec. 12, 2019, which claimspriority from U.S. Provisional Application No. 62/883,696, filed Aug. 7,2019, the contents of which are incorporated by reference in thisapplication.

TECHNICAL FIELD AND BACKGROUND OF THE INVENTION

This invention relates to shielding structures against radiation by theuse of radiation absorbing coal combustion residual components (“CCR”)and other carbon containing materials. More specifically, this inventionrelates to shielding against electromagnetic pulses (EMP), high-altitudeelectromagnetic pulses (HEMP), geomagnetic disturbances (GMD), andintentional electromagnetic interferences (IEMI). The applicationdiscloses structures utilizing CCR and other carbon containing materialsas a radiation-absorbing material per se, and also techniques forenhancing the IEMI and EMP protection afforded such structures. Examplesof structures utilizing CCR are disclosed in applicant's U.S. Pat. Nos.9,790,703 and 9,988,317.

The world has grown dependent upon the use of electronics in nearlyevery facet of life. Safety, security, and normal day-to-day lifeheavily involve the use of electronics. Accidental and intentionalconducted and radiated electromagnetic or geomagnetic emissions arecapable of introducing damaging high electrical currents and voltages.These high currents and voltages are capable of causing disruption, dataloss, and even permanent damage to the targeted electronics. Anincreased level of research and development is being carried out toprotect critical structures, facilities, and components against theseharmful emissions.

Prior art protection against radiation-induced damage has includedgeographic separation, redundancy, technical workarounds, or repairprocedures as long as parts are available. This application disclosesconstructing an Intentional Electro-Magnetic Interference (IEMI)protective barrier using Coal Combustion Residuals (CCR) as a majorcomponent. These barriers can be constructed around EMP protective, ornon-protected EMP structure(s) to provide the additional IEMIprotection. IEMI protective walls can be used to protect many types ofcritical infrastructure systems as outlined by CISA but specificallycontrol centers and electrical substations for utilities will be asector that IEMI protective structures will provide much neededprotection.

It has been verified by testing that CCR absorbs IEMI electromagneticenergy at a greater effective rate than common soils. This greaterabsorption characteristic of CCR allows for a superior IEMI protectivebarrier and at the same time allows for the beneficial use of CCR. TheIEMI barriers can be built with spaced, framed panels, but the preferredembodiment is to construct an IEMI protective barrier berm using CCR.Using CCR in this beneficial use will allow not only for IEMI protectionbut also protection from other destructive forces that an adversary mayuse to damage critical infrastructure, as was perpetrated on Apr. 16,2013 by the Metcalf sniper attack on Pacific Gas and Electric Company'sMetcalf Transmission substation in Coyote, Calif.

The variables for IEMI protective construction apply regarding liners,liner placement, encapsulation, low leaching/low permeability, slopestability, mesh, and mesh placement.

Protection against radiated and conducted electromagnetic emissions suchas HEMP/EMP, GMD, and/or IEMI can be accomplished by the electromagneticshielding methods and devices described in this application. Shieldingcan be applied to CCR facilities and the components, systems, andsubsystems which make up the facility and/or the CCR material itself.Shielding against radiated emissions is accomplished through creating ahighly conductive surface around a protected area to reflect and/orabsorb radiated energy so it does not cause damage. The highlyconductive surface is able to redirect and/or absorb the radiated energyto prevent or minimize exposure to damaging electromagnetic energy.Conducted emissions are generally diverted or blocked through the use offilters with discrete components that pass desired energy and blockundesirable or damaging energy before it enters a protected area.Shielding of radiated and conducted emissions can be accomplishedthrough one or a combination of methods and devices described in thisinvention.

Additionally, EMP has three components which are commonly referred to asE1, E2, and E3. These components vary by frequency, intensity, andlongevity. Shielding against each of these components may beaccomplished by different methods and techniques. One or multiple layersof conductive mesh may be positioned around the entire CCR structure,within the CCR material itself, around specific components orsubsystems, or in natural earth geotechnical formations below orotherwise proximate to the CCR structure. Generally, conductive meshwill provide shielding from EMP events in a lower frequency range;however the size of the free air space within the mesh, commonly knownas the mesh size, will be selected based on the desired frequency rangesthat are required to be protected against.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide shieldingagainst harmful radiated and conducted electromagnetic and geomagneticemissions to structures by incorporating CCR components into thesestructures.

It is another object of the present invention to provide EMP, HEMP, GMD,and/or IEMI shielding to structures having CCR components.

These and other objects and advantages of the present invention areachieved in the preferred embodiments set forth below by providing anelectromagnetic emission shield for protecting a coal combustion residuefacility having a carbon-based material or other electronicallyconductive material. The shield may be formed into an arch andpositioned inside an interior space of the coal combustion residuefacility and a plurality of conductive mesh layers embedded into thecarbon-based material.

In another embodiment of the invention an electromagnetic emissionshield for protecting a coal combustion residue facility has a layer ofcarbon-based material positioned underneath the coal combustion residuefacility and a plurality of conductive mesh layers embedded into thecarbon-based material.

According to another embodiment of the invention, an electromagneticemission shield is provided for protecting a facility having a volumecomprised of coal combustion residue, the shield comprising acarbon-based material positioned inside an interior space of the coalcombustion proximate to and interposed between a potential source ofelectromagnetic emission and the facility.

According to another embodiment of the invention, at least oneelectro-conductive mesh is embedded into the carbon-based material.

According to another embodiment of the invention, the shield comprisesan enclosure having a weight-bearing arched roof.

According to another embodiment of the invention, the shield includes anenclosure having a weight-bearing arched roof, vertical side wallssurrounding the facility, and a slab floor.

According to another embodiment of the invention, the slab floor isundergirded with coke breeze in which is embedding at least one layer ofelectro-conductive mesh.

According to another embodiment of the invention, vertical side wallsare welded to the roof.

According to another embodiment of the invention, an EMP-protectivecomposite structure is provided and includes at least one enclosurehaving walls, a ceiling, at least one ingress/egress portal and a base,each of the walls, the ceiling, the ingress/egress portal and the baseincluding at least one blast-resistant structural panel and at least onelayer of an EMP barrier comprised of CCR that provides magneticconduction, field absorption and field reflection fully-enclosing thestructural panel. The blast-resistant structural panel includes a frameconstructed of spaced-apart frame members of a ferrous material or otherelectrically conductive material, frame reinforcing members or rebarextending between the frame members, a cementitious layer in which theframe is embedded and an EMP or rebar shielding mesh embedded in thecementitious layer. An encapsulation barrier includes an overlying layerof an impermeable cementitious material having a blast-deflectingsurface defining an acute blast-deflecting angle with respect to a majorplane of the base overlying the at least one enclosure, and a HEMPprotective door is formed in the enclosure to absorb and deflect EMP.

According to another embodiment of the invention, the encapsulationbarrier comprises an overlying layer of an impermeable cementitiousmaterial and a layer of vegetation overlying the layer of impermeablecementitious material.

According to another embodiment of the invention, the blast-resistantstructural panel includes an expansion joint extending along a majorside thereof for joining the structural panel to a like structural panelthat allows for movement of the structural panel relative to otherjoined structural panels due to expansion and contraction whilemaintaining intact EMP protective features.

According to another embodiment of the invention, the enclosure includesa plurality of structural panels joined to form enclosed spaces equippedto perform the functions selected from the group of enclosed spacesconsisting of operations center, living quarters, communications, datacenter, mess hall, kitchen facilities, restroom, shower facility,laundry, storage for food, water, medical supplies and equipment,apparel and hygiene-related supplies and equipment, generators, batterystorage, transformers, power substation, power plant SCADA system; fuelsupply, storage for spare and replacement parts for operating equipment.

According to another embodiment of the invention, a circuitous pathextends from an exterior of the EMP-protective structure, through theencapsulation barrier and to the at least one ingress/egress portal ofthe enclosure, the circuitous path configured to absorb and deflect EMPas the EMP passes along the circuitous path, wherein the circuitous pathcomprises a labyrinth having a plurality of right-angle turns, curves,spirals, or baffles though the EMP barrier that provides a two-stageshielding system, —a high frequency “absorptive” section, and a lowerfrequency “Waveguide” magnetic and electric field exclusion system. Thecircuitous path shields against magnetic field conduction and electricfield radiation through absorption and field reflection with respect toelectromagnetic radiation entering the path from the exterior of theEMP-protective structure.

According to another embodiment of the invention, a structural panel foruse in constructing an EMP-protective composite structure is provided,the structural panel including spaced-apart frame members of a ferrousmaterial, frame reinforcing members extending between and connecting thespaced-apart frame members; and a cementitious layer in which the frameis embedded.

According to another embodiment of the invention, an EMP absorbing meshis embedded in the cementitious layer.

According to another embodiment of the invention, the blast-resistantstructural panel includes an expansion joint extending along a majorside thereof for joining the structural panel to a like structural panelthat allows for movement of the structural panel relative to otherjoined structural panels due to expansion and contraction whilemaintaining intact EMP protective features.

According to another embodiment of the invention, an insulation layer isprovided coextensive with a major surface of the panel.

According to another embodiment of the invention, the panel is adaptedto be fabricated in a horizontal position and then tilted in situ intoan upright position to form a part of the enclosure.

According to another embodiment of the invention, the cementitious layeris selected from the group consisting of lightweight concrete, epoxyconcrete, ultra-high performance concrete and autoclave concrete.

According to another embodiment of the invention, an RF filter isprovided that includes an electrically-conductive pipe defining a voidfilled with carbon-containing materials to provide high-frequencyfiltering, and enclosed on both ends by end caps including openingsthrough which extend respective electrical stress-protected bushings, anelectrically-conductive cable extending through the length of thefilter, the filter adapted to be positioned to extend between an RFunshielded area through a shield to a shielded area of a facility to beprotected from RF.

According to another embodiment of the invention, a plurality of RFfilters are positioned in spaced-apart position relative to each otherfor providing RF shielding to the facility.

According to another embodiment of the invention an RF filter isprovided that includes a plurality of electrically-conductive elementsdefining a void filled with carbon-containing materials to providehigh-frequency filtering, and enclosed on both ends by through whichextend respective electrical stress-protected bushings. Anelectrically-conductive cable extends through the length of each of thefilter elements, and the filter elements are positioned in an arraywithin an enclosure, the enclosure having a RF shield positioned withinthe enclosure defining on one side an RF shielded area and on anotherside an RF unshielded area, and through which the filter elements extendinto and from an area of a facility to be protected from RF.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

The present invention is best understood when the following detaileddescription of the invention is read with reference to the accompanyingdrawings, in which:

FIG. 1 is a top roof plan view of an EMP protective structureincorporating EMP absorbing materials such as meshes and coal combustionresiduals and/or coke breeze;

FIG. 2 is a side elevation/cross section of the protective structureshown in FIG. 1;

FIG. 3 is a side elevation/cross section of an EMP protective structureincorporating EMP absorbing materials such as meshes and coal combustionresiduals and/or coke breeze;

FIG. 4 is a front view of a wall section for use in EMP absorbingmaterials such as coal combustion residuals and coke breeze;

FIG. 5 is a side elevation of the wall section shown in FIG. 4;

FIG. 6 is a top view of three wall sections of FIGS. 4 and 5;

FIG. 7 is a perspective view with parts cut away of the wall section ofFIGS. 4 and 5;

FIG. 7A is a cross-section of an expansion joint construction used toconnect adjacent walls.

FIG. 8 is a schematic side elevation of an EMP Shielded facilityincorporating coal combustion residuals and other EMP absorbingmaterials;

FIG. 9 is a top plan view of another protective structure incorporatingEMP absorbing materials such as coal combustion residuals and/or cokebreeze;

FIG. 10 is a side elevation of the protective structure shown in FIG. 9;

FIG. 11 is a side elevation of an alternative protective structure;

FIG. 12 is a side elevation of another alternative protective structure;

FIG. 13 is a top plan view of a protective structure showing details ofsecure room facilities;

FIG. 14 is a side elevation of a protective structure showing details ofsecure room facilities;

FIG. 15 is a top plan view of an alternative protective structureindicating secure rooms protected by the structure;

FIGS. 16 and 17 are side elevations of a dome-shaped EMP protectivestructure;

FIG. 18 is a perspective view of a carbon-based radio frequency (RF)filter;

FIG. 19 is a view of a filter element of the carbon-based radiofrequency (RF) filter of FIG. 18;

FIG. 20 is a perspective view of an application of a filter element of acarbon-based radio frequency (RF) filter according to FIGS. 18 and 19;

FIG. 21 is a table showing Coal Ash IEMI Absorption test data results;

FIG. 22 is a table showing Material Absorption probe test data results;

FIG. 23 is a vertical cross-section of an elongated IEMI protective bermincorporating coal combustion residuals;

FIG. 24 is a top plan view of a secure compound surrounded by anelongated IEMI protective berm according to FIG. 23;

FIG. 25 is a partial vertical cross-section of a secure compoundsurrounded by an elongated IEMI protective berm according to anotherembodiment; and

FIG. 26 is a perspective view of the secure compound of FIG. 25.

GENERAL DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiments shown in the drawing figures have certain features incommon which are described below before providing specific details ofthe individual drawings. In general, enhanced radiation absorption inCCR structures is achieved by use of various panels and walls thatinclude a radio frequency shielding mesh. The mesh may be welded, wovenwire fabric, tied together with tie wire to form a continuous secureconnection, formed with end loops having a threaded round or oval barthat runs perpendicular to the loops to tie the sections of meshtogether, or formed with a hook and claw method. The mesh may be made ofcarbon steel, or any other material that can effectively conductelectricity and/or magnetic fields. The mesh may be coated and/or dippedto prevent corrosion. Corrosion may be due to the varying PH balances inthe CCR material. Commercially available industrial coatings areenvisioned as well as specifically developed coatings.

Conductive material, other than meshes, which produce the same orsimilar results, may be placed within the CCR structure, components, orCCR material itself. Shredded scrap metal, such as from vehicleshredders, steel fibers, textured glass, and other similar products canbe utilized in and around structures having CCR components. Texturedglass and shredded scrap metal may be used. These materials can be mixeddirectly into the CCR material itself, or formed into defined sectionsplaced in and/or around the structure, for example arched, vertical,and/or horizontal formations. The material could also be placed in asection of soil located in the CCR structure or below the slab-on-gradeportion of the interior structure which may be designed to be in acarbon-based material (a.k.a. carbon-containing material), other thanCCR, CCR and soil, or any other acceptable material that will providethe desired shielding.

EMP absorption may be optionally enhanced by various additives andconstructions which increase carbon content of the CCR structure. SomeCCR structures already have high carbon content and may not require anyenhancement. A carbon-based material, such as coal coke breeze or petcoke, may be in the form of an additive within the CCR material itself,or positioned as a defined construction proximate to or within theinterior space of the CCR structure to enhance absorption within adefined frequency range. Carbon-based material may be used singularly orin combination with other carbon enhancing materials. It is alsoenvisioned that carbon-based material may be attached to a liner orother barrier.

CCR material compositions typically vary in carbon content within aspecific site or different sites. This variation may determine the size,type, and/or thickness of other elements of the CCR shielding required.These variables will be the main determining factors in the amount andextent of any carbon enhancing material required.

An arch is one specific technique for providing shielding of the typeenvisioned in this application. The percentage of carbon in the arch maybe determined by the aforementioned site-specific variables, or ageneral predetermined amount, and the placement of the interior spacesin relationship to the bottom of the CCR. It is envisioned that theother shapes or configurations such as vertical sides and horizontaltop/bottoms may be utilized in combination with arch structures.Construction of vertical wall/panel sections may be accomplished byusing construction trench boxes. A floor shield may also be formed ofmesh and/or a defined layer of a carbon-based material positionedunderneath the floor of the interior structure. The entire mass of CCRmaterial itself can be increased in carbon content in lieu of placementwithin the CCR structure depending on the type and amount ofelectromagnetic shielding required.

A combination of carbon enhancing material and mesh may be utilized toprevent electromagnetic or geomagnetic forces from penetrating upwardsinto the interior spaces of the CCR structure. While two layers of meshand three layers of carbon enhancing material are shown, the amount,type, and thickness of the layers is dependent upon site specificrequirements. The mesh may be fastened to sheet piling or spaced framemetal panels by welding, bolted bus bar type connection, and/or anyother fasteners that are capable of producing a continuous metal tometal connection. Mesh from the exterior side of the interior space wallmay be connected at an equal elevation or a lower elevation point tocreate a continuous 360 degree shielding around the interior spaces.

When the interior spaces of a CCR structure are constructed out ofprecast concrete or poured-in-place concrete, a metal plate may beinserted into the concrete to have a connection point for the mesh onboth the interior and exterior sides of the interior space. Often it isnecessary to test the properties of the installed shielding. A systemfor testing may be integrated into the CCR facilities for continuous ordiscrete testing. One testing system has multiple loop coils which maybe energized so that the amount of energy emanating into the protectedareas may be measured. These measurements enable the shieldingeffectiveness to be calculated so that the integrity of the shieldingcan be determined. Testing may also be accomplished by directlyenergizing conductive meshes around the facility using differentfrequencies and power levels so that shielding effectiveness may becalculated in protected areas to give confidence in the overall level ofshielding that is present inside the CCR structure.

Radio frequency (RF) absorption can be tested using specially fabricatedprobes. These probes use copper tubes that have a pre-determined crosssection diameter and length (for example, 1 inch in diameter and 10 feetin length) with caps and/or attachments that allow for the use ofdemountable components such as RF-type connectors, clips, or other meansof connecting/disconnecting the probes.

The probes are energized with RF energy of any frequency. A typicalfrequency range is from 10 kHz to 1 GHz or higher for IEMI. RF energy isinjected on one end of the probe, and the remaining energy is removed onthe opposite end of the probe. The probes can be used to characterizethe absorption properties of any material. The difference betweeninjected energy and harvested energy is the absorption of energy alongthe probe. When the probe is placed or buried within various materialsthe inherent ability to absorb RF of the material surrounding the probemay be determined when a frequency of a predetermined bandwidth is sweptacross the spectrum. Additionally, when the probes are buried in CCR,the ability of CCR to absorb, for example, HEMP/EMP energy from 10 kHzto 1 GHz can be determined. This allows for the suitability of CCR forHEMP and IEMI shielded structures to be determined.

Air and/or personnel entryways into the CCR structure may be createdthrough the use of an RF absorber in conjunction with a Waveguide BelowCutoff (WBC). The entryway will be comprised of an RF absorber, such asencapsulated CCR, coke breeze, MET coke, PET coke (containing varyingpercentages of carbon) or other carbon or non-carbon absorbing materialwith welded steel or welded steel mesh embedded in the RF absorber andconfigured to create a WBC. The entryway will function such that lowfrequency electromagnetic waves will be blocked by the WBC and higherfrequency electromagnetic waves (above the cutoff frequency) will beabsorbed by the RF absorber thereby creating a personnel or air entrywaycapable of blocking RF energy without utilizing an RF door. The entrywaypath may or may not curve or turn to help facilitate RF absorption. Theentryway may include rudimentary RF shielding doors, turnstiles, orother RF absorbing features to improve overall RF shielding performance.

The removal of RF energy from wires, cables, conduits, pipes or othermetallic fixtures may also be necessary. Wires, cables, conduits, pipesor other metallic fixtures may be embedded within materials such asencapsulated CCR, coke breeze, MET coke, PET coke (containing varyingpercentages of carbon) or other carbon or non-carbon absorbing materialto significantly reduce high-frequency RF energy. This has applicationsfor power lines, signal lines (such as those in power substations),control lines (such as those in power substations), and metallic pipes(such as water/sewer/gas lines) that may not be otherwise configured toexclude RF energy.

An electromagnetic filter may be created out of utility-grade discretecomponents. Air-core inductors, or other types of inductors that are ofthe type in use by electric utilities along with capacitors of the typethat are used by electric utilities for power factor correction, orother purposes may be used to create a filter. This filter can beutilized independently or in conjunction with other filters to provide arange of frequencies or attenuation levels required by a particularapplication. One example is a HEMP filter (from 10 kHz to 1 GHz ormore).

Medium-voltage power bus bars may be created to feed power into a CCRstructure. The bus bar may be 10 ft or longer in length and ofsufficient cross-section to transmit electrical power without excessiveheating. The bus bar may not conduct significant amounts of RF energy.The bus bar may be insulated with nylon, PVC, Sulfur Hexaflouride Gas,or other insulating material or combination of insulating materials. Thebus bar may be embedded in encapsulated CCR, coke breeze, MET coke, PETcoke (containing varying percentages of carbon) or other carbon ornon-carbon absorbing material which will act as an RF absorber and willprevent significant RF energy from being transmitted by the bus bar. Thebus bar may be used in conjunction with the filter to operate across theentire HEMP pulse spectrum.

This arrangement might be used for applications like electric powersubstation houses where multiple conductors may need to pass from anunshielded area to a shielded area, and applications (such as high-speedprotective relays) that may not be compatible with conventional filters,as is sometimes the case. Grounding shields from the cables would beremoved for the portion of the conductors that pass through the carboncontaining absorbing material. However, the carbon RF filter is utilizedit will be configured so that one end is outside of the shieldedenvironment, and the other end is inside the shielded environment

Inside of the RF shielded environment, other protective devices, such asmetal-oxide varistors may be employed to reduce any remaining RFartifacts. With higher frequency RF artifacts removed, MOVs may beeffectively employed. Often when high-frequency artifacts are present,an MOV does not act fast enough to protect against conducted RF energythat may be damaging. With the higher frequency artifacts removed, the“rise time” of any RF energy will be significantly less, allowing forconventional and/or less expensive MOVs that have a slower rise-timeresponse to be used to provide more effective protection to a conductorin a shielded environment.

One of the technical principles employed with this invention is calledthe “Skin Effect.” The skin effect is the tendency of a high-frequencyalternating current, such as radio frequency energy, to becomedistributed within an electrical conductor in a way that the current ismostly carried near the surface of a conductor (aka: “the skin” of theconductor). The depth of the “skin” is dependent upon frequency of theelectrical current—so DC power would utilize the whole conductor,utility AC power would have very limited skin effect, because it is lowin frequency, and RF energy from an EMP or IEMI or other RF source wouldflow mainly on the outside of a conductor. By flowing on the outside ofthe conductor, the RF energy is closer to the carbon-containing materialthat absorbs the RF energy. This allows the RF energy to be removed fromthe conductors as it propagates across the conductor. Another technicalprinciple employed with this invention is “re-radiation” of RF energythat is travelling down a conductor. As RF energy frequency increases,the tendency for RF energy to reradiate from conducted energy to energytraveling in free-space (or within some other medium in which aconductor is placed) as it travels along the conductor. When the energyreradiates in carbon-containing material, it is absorbed and convertedto heat by the carbon, which is the same principle that pyramidal carbonabsorbers, commonly used in “anechoic chambers” or EMP testing chambers.

For applications with utility AC power or DC power from alternativeenergy (as examples, but not limited to these examples) thecarbon-containing RF absorber will absorb any energy that is reradiatedfrom a conductor inside of it. The effectiveness of thecarbon-containing RF absorber will be dependent on the thickness of theRF absorber, with higher frequencies (that have a shorter wavelength)being absorbed by a shorter thickness of carbon material in which agiven conductor may be embedded than for lower frequencies (with alonger wavelength).

The EMP Protective composite enclosure panel systems and materials inthis application have unique features that allow for, if required,exceptional corrective and maintenance work which can be easily locatedand performed to allow for long-term Intentional Electro MagneticInterference (IEMI) and EMP shielding, absorption and conductivityprotection requirements of the system(s) for many decades, if notlonger, to come.

IEMI weapons generally have a frequency spectrum from 80 MHz-10 GHz (orhigher) and project either a narrow-band repetitive pulse, a wide-bandrepetitive pulse, or some other pulse modulation scheme designed todamage, disrupt, or upset electronic systems that are in their antennafocus area. The maximum field-strength beam of IEMI weapons is generallynarrow (a few degrees wide in beam-width) and can often be aimed tofocus on specific systems or areas of a building.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now specifically to the drawings, FIG. 1 is a roof plan of astructure 10 adapted to contain and protect any suitable facility fromEMP. The structure 10 is surrounded by CCR acting as a primary EMPshielding (not shown). The structure 10 includes a roof 12 and a heavy,robust structure 14 that protrudes above the level of the roof 12 andcontains wave guides 16 that are tuned to intercept EMP radiation atpredetermined frequencies. The structure 14 may include a communicationsantenna 18, as shown. FIG. 2 illustrates that the structure 10 includesvertical slab walls 20, 22 with a slab floor 24 set on grade. An EMPprotector panel 26 is set below grade, as shown, and includes waveguides 28 that are tuned to intercept EMP radiation at predeterminedfrequencies. The structure 10 is anchored below grade by largefoundation piers 30. A below grade foundation pad 32 is positioned underthe EMP protector panel 26 and includes a slab of an EMP absorbingmaterial such as coke breeze into which is embedded a mesh 34, which mayinclude multiple layers. The combination of the coke breeze and the mesh34 provide enhanced EMP absorbing capability to the structure 10, whichas noted above is embedding in a thick layer of CCR and one or morelayers of mesh, not shown.

FIG. 3 is a side elevation/cross section of an EMP protective structure40 incorporating EMP absorbing materials such as coal combustionresiduals and coke breeze. The structure 40 is shown surrounded by alarge, deep volume of CCR. The entire structure is shown encapsulated inan additional layer 42 of dirt and/or CCR. The structure 40 includesvertical slab walls 44, 46 with a slab floor 46 set on grade. Thestructure 40 also includes a lightweight, sloped concrete roof 48. Thetop of the structure 40 is enclosed with a slab 50 of coke breeze inwhich is embedded one or more layers of a mesh 52. The combination ofthe coke breeze and the mesh 52 provide enhanced EMP absorbingcapability to the structure 40. Similarly, the slab floor 46 isundergirded with a slab 54 of coke breeze in which is embedded one ormore layers of a mesh 56. The structure 40 is anchored below grade bylarge foundation piers 58.

The meshes in the slabs 50 and 54 are welded and/or electronicallyconnected to the vertical slab walls 44, 60, which are concrete andsteel.

The details of the slab walls, for example wall 44, are shown in FIGS. 4and 5. As shown, wall 44 is formed of a rectangular steel frame 62 andincludes a grid of mesh 64 formed of an interlocked array of rebar orsimilar interlocking elongate elements placed in the concrete 70 insideof the frame 62. As best shown in FIG. 5, the frame 62 has a back wallpanel 66 to which are welded concrete anchor studs 68. The frame 62 thusforms a shallow vessel into which concrete 70 is placed. This concrete70 can be EMP protective with the addition of carbon-based material aspart of the concrete mix design, can provide a redundancy of EMPprotective above the back wall panel 66.

FIG. 6 is a top view of three walls 44 of FIGS. 4 and 5, shown weldedtogether end-to-end to form a three-wall panel.

FIG. 7 is a perspective view with parts cut away of the wall 44 of FIGS.4 and 5.

There are many different design features which can be used when thepanels, for example, wall panels 44, are used for vertical slab walls,floor or roof components in a structure. FIG. 7A shows the use of anexpansion joint 45 connected by welding adjacent vertical slab wallpanels 44. The expansion joint 45 allows for movement of the structuredue to expansion and contraction, but at the same time provides for theEMP and IEMI protective features to stay intact. The expansion joint 45extends along the vertical length of the walls and spaces the adjacentwall panels 44 apart. The expansion joints 45 are connected bycontinuous welds. The outwardly-projecting face of the expansion joint45 permits movement of adjacent wall panels 44 relative to each other.This movement is converted into a corresponding flexure of the expansionjoint 45 in an outward and inward movement.

Referring now to FIG. 8, a schematic side elevation of an EMP Shieldedstructure 80 incorporating coal combustion residuals and other EMPabsorbing materials. The design protects the structure 80 from damagingelectromagnetic forces penetrating upwards from the ground or bottomportion into the interior spaces 90 and 84 of the structure 80. Thestructure 80 includes a shallow arch 82 constructed of carbon containingmaterial such as coke breeze which contains one or more layers of mesh.An occupancy area 84 is positioned in the center of the structure 80.Also formed of pre-cast or poured-in-places reinforced concrete and inthe embodiment of FIG. 8 are a series of parallel arched structures 90that sit under the shallow arch 82 and are interior secure spaces. Thesestructures 90 are overburdened with a relatively shallow layer ofcarbon-containing or carbon supplemented material 86, for example,containing 10 percent carbon, and a massively thick layer of CCR 88.

The structure 80 includes a shielded air intake 92, a shieldedpersonnel/material entryway 94, a power filter vault 96, and a powerentryway 98. Two layers of mesh shielding 100 reside within therelatively shallow layer of carbon-containing or carbon supplementedmaterial 86. A floor plate 102, which may be a composite panels, steelplate, a mesh, or a combination of the two or more, embedded in carboncontaining material such as coke breeze and/or CCR provides primaryprotection against electromagnetic energy penetrating upwards from theground or bottom portion into the interior spaces of the structure 80.

FIGS. 9 and 10 show a top plan and side elevation of another protectivestructure 110 incorporating EMP absorbing materials such as coalcombustion residuals and/or coke breeze, by way of example, thestructures shown in FIGS. 1-8 that provide enhanced protection,particularly for the sides and underside of the structures. The volumeof the structure 110 is principally defined by CCR. A secure room 112 isaccessed by a raceway 114 providing utilities and an emergency exit. Anentryway 116 with a right angle jog provides normal ingress and egress.An alternative entryway 118 defines a labyrinth of right angle jogs thatprevent electromagnetic intrusion. The entire secure room is surroundedby low frequency mesh shielding 120 as described above. As best shown inFIG. 10, the secure room 112 is protected from the bottom by a slabfloor 122 containing coke breeze and one or more layers of mesh as anEMP absorbing material. The structure 110 may be covered with a HDPEcover 124, over which may be placed a vegetative cover 126 that providestemperature control and camouflage.

Referring to FIG. 11, an alternative protective structure 130 is shown,which has a volume defined principally by CCR. The sloped sides enclosesecure rooms 132, 134 the bottom of which is protected by a slab 136containing coke breeze and one or more layers of mesh. The perimeter ofthe rooms 132, 134 is surrounded by low frequency mesh shielding 138 asdefined in this application.

FIG. 12 is a side elevation of another alternative protective structure140 and may be any desired size, including for example, 13.5 millioncubic yards. The structure 140 rests on a conventional prepared subgradefoundation 142 covered with a liner system 144 that prevents any runofffrom the structure 140 from entering the ground through the foundation142. The principal component of the volume of the structure 140 isdensely-compressed CCR 146 that is encapsulated under a reinforced CCRcap 148. A liner system covering 150 encloses the CCR 146 and CCR cap148. All or part of the structure 140 may be covered with soil andvegetation 152.

As shown in FIG. 12, the structure 140 has severely-sloped sidewallsdesigned to deflect a blast proximate the structure 140. The structure140 is adapted to store, for example, bulk storage items in separatereinforced rooms 154 protected by a further reinforced enclosure 156.Rooms 154 and the reinforced enclosure 156 are constructed according tothe construction principles utilizing the composite enclosure panelsystem identified in this application to achieve an EMP-protected areawithin the structure 140.

FIGS. 13 and 14 are a top plan view and side elevation of a protectivestructure 160 showing details of secure room facilities that includelabyrinth-type ingress/egress access tunnels 162, 164 within slopingwalls 166 that connect the exterior of the structure 160 with theinterior “X” of the structure 160. The interior ““X” of the structure160 includes necessities for sustaining life for an extended time,including lines 168 delivering electric power to the structure 160,fluid lines 170 for delivering and conveying away water, sewage and thelike, a water storage tank 172 that can be gravity fed when necessarythrough a feed line 174 from a reservoir 176. Electric power can begenerated by a generator 178 when electric r current from exterior thestructure 160 is not available. Combustion gases from the generator 178and ventilation of other gases is by an exhaust stack 180. Storage silos182 provide storage for food, water and any other materials that arerequired.

FIG. 15 is a top plan view of an alternative protective structure 200indicating secure rooms 202 protected by the structure 200. Thisstructure 200 may be any desired size, including for example, 13.5million cubic yards comprising compacted CCR. Continued reference toFIG. 15 indicates labyrinth-type ingress/egress access tunnels 204, 242,206 that connect the exterior of the structure 200 with the rooms 202.The rooms 202 are connected by passageways 210 that connect with theaccess tunnels 204, 242, 206, and 210.

Further details of the manner in which various structures are providedwith enhanced EMP protection are shown in FIGS. 16 and 17. In FIG. 16 aprotective structure 220 is enclosed within a larger structurecomprising compacted CCR, as described and shown above. The structure220 includes an arched roof 222 formed of layers of specific materialsdesigned to provide enhanced protection against EMP. An innermost steelplate 224 provides structural support for a concrete layer 226, which isovertopped by a layer 228 of waterproofing, and a layer 230 of EMPabsorbing coke breeze. A vapor barrier 232, for example HDPE enclosesthe entire roof 222.

The sidewalls 244, 242 of the structure 220 include an exterior concretestructure 242 supported by a metal casement 244. A further secondarynon-structural carbon heavy concrete layer 246 provides innermostprotection. The base of the structure 220 is supported on crushed stone,for example, a six-inch bed 250 of ¾ inch stone. A mat foundation 252enclosed within a vapor barrier 254 supports the sidewalls 240. The matfoundation 250 supports a slab 256 formed of, for example, a 6 inchconcrete slab on grade. The coke breeze 252 includes embedded EMPabsorbing mesh 258 extending throughout the length and width of the cokebreeze or other carbon containing material.

Further details of the metal casement 244 are shown in FIG. 17, andinclude continuous welds 260, holes for rebar placement 262, and mesh258 with flat bars 254.

Referring now to FIGS. 18, 19 and 20, the use of carbon andcarbon-containing materials for the purposes of absorbing and/orremoving radio frequency (“RF”) energy from wires, cables, conduits,pipes, electrical conductors or other metallic fixtures. The RF energycan come from a High-Altitude Electromagnetic Pulse (“HEMP” or “EMP”)that is absorbed and conducted along conductive element, energygenerated with an electronic device that is directly connected to aconductive element such as a wire, power conductor, or utility feedercommonly known as an Intentional Electromagnetic Interference (“IEMI”)device, or energy that is absorbed and conducted along a conductiveand/or metallic element from an IEMI device that is connected to anantenna that radiates IEMI energy so that a wire, cable, conduit, pipe,electrical conductor, or metallic fixture absorbs and conducts thispotentially harmful energy.

A carbon RF reduces conducted RF energy on a conductor, whether directlysuperimposed on the conductor, or whether superimposed onto a conductorthrough free-space or other material. This carbon may be CCR, graphite,coke breeze, PET coke, calcined coke, or other carbon-containingmaterial that is capable of absorbing RF energy. The carbon containingmaterial may be configured in mats or sheets, it may be in granular formin various particle sizes, or it may be in any other form, provided ithas the RF absorbing characteristics. Embedding a conductor incarbon-containing materials can act as an absorber of RF energy thattravels along the conductor. This effect is such that a conductor thusconfigured acts as a filter, allowing the passage of intendedlow-frequency signals, such as electrical power in alternating current,or direct current forms, or low frequency signals such as those used insome sensors and actuator controls.

One specific embodiment of this feature is in electrical power into anRF shielded structure (this can include a HEMP shielded structure, anIEMI shielded structure, or a combination of both or any other structurethat is designed to limit the incursion of RF energy into aprotected/shielded space. A structure that has other applications (suchas an “All-Hazard Total Protective Structure”) may also be RF shielded.Such a filter constructed in this way can be effective at differentvoltages, even voltages commonly referred to in electrical utility termsas “Low-Voltage”, “Medium-Voltage” or “High-Voltage” intended to referto voltages from 0 Volts to voltages measured in the hundreds ofthousands of volts or higher.

For example, a power line that is run through a carbon RF filter of thistype will pass 60 Hz AC or Direct Current but will significantly reduceRF energy that may be intentionally or unintentionally travelling alongthe same conductor. This differs significantly from a typical RF filterthat may be comprised of inductors and capacitors as commerciallyavailable because these filters will generally have some loss associatedwith their use. The carbon RF filter is a significant improvement overconventional filter technologies in that losses are eliminated otherthan those that are typically experienced in the same conductor notembedded in carbon-containing material for the purposes of carryingelectrical current.

The filter may or may not be constructed so that conductors pass into ametallic enclosure (with proper insulation and electrical stressprotection on the conductor entry and exit) that holds carbon containingmaterial. In the event of an electrical fault, any current will besafely contained within the enclosure and safely allow for the “fault”to be cleared by typically used electrical equipment, such as fuses orbreakers or other protection means. This type of shielding is requiredfor conductors above a certain voltage level.

Conductors embedded in carbon may include those typically available fromelectrical conductor vendors, or it may be a specially designedconductor that is specially insulated inside of a nylon or PVC (or otherelectrical insulating material) tube. The use of SF6 (sulfurhexafluoride) or dry air or other material or gas may be used to createan insulating barrier inside of a non-conductive enclosure or pipe thatallows for a metallic busbar (such as copper) to be embedded incarbon-containing material. The conductors, when appropriate as dictatedby the electrical code, may be embedded directly in carbon-containingmaterial with no specific enclosure.

The carbon containing material may be in a mat or sheet form and may bewrapped around individual conductors to provide RF absorbing/filteringcharacteristics.

As shown in FIG. 18 an RF filter 280 includes steel or other ferrous ornon-ferrous conductive pipe 282 enclosed on both ends by steel ornon-conductive threaded end caps 284, 286. The end caps 284, 286 includeopenings through which extend respective bushings 288, 290, which may beelectrical stress-protected connectors. The bushings 288, 290 connectwith an electrically-conductive cable 292 that extends through thelength of the filter 280. The cable 292 may be insulated, or may be adielectric/insulating insert with the cable 292 extending through theinsert. The pipe 282 defines a void, and the void is filled withcarbon-containing materials, as described above, to providehigh-frequency filtering. Multiple elements can be arranged to act as RFfilters for 3-phase power, DC power from photovoltaics as examples, butnot the only possible applications.

FIG. 19 illustrates another possible RF filter 300 that utilizes a metalbox 302 in which an array of conductors 304 is positioned. The exteriorof the box 302 is provided with an RF attenuating barrier 306, such as amesh as described in this application. The box is filled with acarbon-containing RF absorbing material such as coke breeze or one ofthe other carbon-based materials described above.

Referring now to FIG. 20, the above-described RF filters 280, and 300,not shown, can be used for applications like electric power substation310 where multiple conductors 280 may pass from an unshielded areathrough a shield barrier 312 to a shielded area of the substation 310,and applications (such as high-speed protective relays) that may not becompatible with conventional filters. Grounding shields from the cableswould be removed for the portion of the conductors that pass through thecarbon containing absorbing material. However, the carbon RF filter 180or 200 is utilized it will be configured so that one end is outside ofthe shielded environment, and the other end is inside the shieldedenvironment, as shown in FIG. 20. Inside of the RF shielded environment,other protective devices, such as metal-oxide varistors may be employedto reduce any remaining RF artifacts.

Transient suppression devices can take on many forms from arc contacts,to filters, to solid state semiconductor devices. Discrete semiconductortransient suppression devices such as the Metal-oxide Varistor, or(“MOV”), are by far the most common as they are available in a varietyof energy absorbing and voltage ratings making it possible to exercisetight control over unwanted and potentially destructive transients orover voltage spikes. With higher frequency RF artifacts removed, MOV'smay be effectively employed. Often when high-frequency artifacts arepresent, an MOV does not act fast enough to protect against conducted RFenergy that may be damaging. With the higher frequency artifactsremoved, the “rise time” of any RF energy will be significantly less,allowing for conventional and/or less expensive MOV's that have a slowerrise-time response to be used to provide more effective protection to aconductor in a shielded environment.

FIGS. 21 and 22 are tables showing Coal Ash IEMI absorption test dataresults and Material Absorption probe test data results, respectively.

Referring now to FIGS. 23, 24, 25 and 26, alternatives to the fullyenclosed CCR structures disclosed above are explained. In somecircumstances it may be impractical to enclose large facilities fullywith vast quantities of CCR. In such circumstances large facilities, forexample, utility power stations, military structures and similarfacilities can be positioned within an open berm structure. The bermstructure can provide protection against low level, low angle IEMI bydeflecting the IEMI up and over the facilities within the open bermstructure.

For example, a berm 340 is shown in cross-section and has an isoscelesor three sides equal trapezoid shape, with a relatively wide base 342,opposed inner and outer sloped walls 344, 346 surmounted by a relativelynarrow top 348. The top 348 may be configured as a roadbed along whichsecurity or service vehicles may travel. The volume of the berm 340 iscomprised of compacted CCR and other EMP absorbing materials, asdescribed above. The berm may include a security fence. The base 342 ofthe berm 340 may be protected using the enclosure techniques describedabove.

Referring to FIG. 24 is a top plan view of a secure compound surroundedby the elongated EMP protective berm 340 according to FIG. 23. The berm340 defines a secure perimeter with an ingress/egress 360. Vehiclesaccess a parking lot 362 via a driveway 364. The compound can includeany desired structures, for example offices 366 and warehouses 368. Theheight of the perimeter berm 340 is determined by the height of thestructures within the enclosure of the berm 340. Ideally, the height ofthe berm 340 will be at least as high as or higher than the higheststructure within the perimeter.

FIG. 25 is a partial vertical cross-section of a secure compoundsurrounded by an elongated EMP protective berm 370 according to analternative embodiment having a right isosceles shape with a wide base372, outwardly facing, protective sloping side 374 surmounted by arelatively narrow top 376. The top 376 may serve as a roadbed. The innerwall 378 is vertical and thus occupies less interior space than otherdesigns. The vertical inner wall 378 may be supported by a separatebarrier wall 380. As with the other berm embodiments, the volume of theberm 370 is comprised of compacted CCR and/or other IEMI absorbingmaterials, as described above.

FIG. 26 is a perspective view of the secure compound and berm 370 ofFIG. 25.

An electromagnetic emission shield for protecting a coal combustionresidue facility according to the invention have been described withreference to specific embodiments and examples. Various details of theinvention may be changed without departing from the scope of theinvention. Furthermore, the foregoing description of the preferredembodiments of the invention and best mode for practicing the inventionare provided for the purpose of illustration only and not for thepurpose of limitation, the invention being defined by the claims.

What is claimed is:
 1. A structural panel for use in constructing anEMP-protective composite structure, the structural panel comprising: (a)spaced-apart side frame members and spaced-apart end frame members of aferrous material defining a frame; (b) frame reinforcing memberscomprising a grid formed of mutually-interlocking array of elongateelements defining a mesh extending between and connecting thespaced-apart side and end frame members defining the frame to form ashallow vessel for receiving a cementitious layer; (c) a cementitiouslayer in which the frame and the elongate elements defining a mesh isembedded; and (d) a back wall panel covering and enclosing a first majorsurface of the structural panel and connected with the side and endframe members to define an enclosure for five sides of the structuralpanel.
 2. A structural panel according to claim 1, wherein the mesh isan EMP absorbing mesh embedded in the cementitious layer.
 3. Astructural panel according to claim 1, wherein the blast-resistantstructural panel includes an expansion joint extending along a majorside thereof for joining the structural panel to a like structural panelthat allows for movement of the structural panel relative to otherjoined structural panels due to expansion and contraction whilemaintaining intact EMP protective features.
 4. A structural panelaccording to claim 3, and including insulation layer coextensive with amajor surface of the panel.
 5. A structural panel according to claim 1,wherein the cementitious layer is selected from the group consisting oflightweight concrete, epoxy concrete, ultra-high performance concreteand autoclave concrete.